During this coming year we plan to continue our laser homodyne scattering study of the effects of saliva on bacterial aggregation. In the next 2 months we expect to have detailed experimental information on the aggregating characteristics of bacteria suspended in saliva from caries-resistant and caries-prone individuals, as well as differences in activity between the submaxillary and parotid fluids. If these experiments confirm our preliminary data, we may be able to develop a clinical testing procedure for identifying caries-prone children. In the coming year we shall attempt to identify isolated specific factors such as glycoproteins which may be responsible for the observed changes. We also plan to analyze the significance of interactions between different plaque bacteria in establishing aggregate size, structure and stability. We expect to study the effects on aggregation of oral factors such as secretory IgA, calcium, dextran, etc. We wish to determine the adherence strength of bacteria to solid substrates and the aggregation characteristics of bacteria suspended in ground enamel or hydroxyapatite as a function of bacterial species and different environmental factors such as saliva, dextran, etc.